Abstract: Measurements made with a multicomponent logging instrument when used in a substantially horizontal borehole in earth formations are diagnostic of the direction of beds relative to the position of the borehole. When the logging instrument is conveyed on a drilling assembly, the drilling trajectory may be maintained to follow a predetermined trajectory or to maintain a desired distance from a boundary such as an oil-water contact.

Abstract: Cross-component measurements made at a plurality of toolface angles are processed to remove bias. The amplitude of the resulting sinusoid is used to estimate a distance to an interface in an earth formation.

Abstract: An improved induction tool for formation resistivity evaluations. The tool provides electromagnetic transmitters and sensors suitable for transmitting and receiving magnetic fields in radial directions that are orthogonal to the tool's longitudinal axis with minimal susceptibility to errors associated with parasitic eddy currents induced in the metal components surrounding the transmitter and receiver coils. Various transmitter receiver combinations are provided to select sensitivity to a desired reservoir formation properties, for example, different orientations xy, xz, yz, 20-40, 20-90, and combinations, such as, Symmetric-symmetric; Asymmetric-symmetric; and Asymmetric-asymmetric. Measurements made with a multi-component logging instrument when used in a substantially horizontal, vertical or deviated borehole in earth formations are diagnostic of the direction of resistive beds relative to the position of the borehole.

Abstract: A transverse induction logging tool having a transmitter and receiver for downhole sampling of formation properties, the tool having a symmetrical shielded split-coil transmitter coil and a bucking coil interposed between the split transmitter coils to reduce coupling of the transmitter time varying magnetic field into the receiver. The tool provides symmetrical shielding of the coils and grounding at either the transmitter or receiver end only to reduce coupling of induced currents into the received signal. The tool provides an insulator between receiver electronics and the conductive receiver housing having contact with conductive wellbore fluid, to reduce parasitic current flowing in a loop formed by the upper housing, feed through pipe, lower housing and wellbore fluid adjacent the probe housing or mandrel. An internal verification loop is provided to track changes in transmitter current in the real and quadrature component of the received data signal.

Abstract: The present invention improves measurement of the formation induction response in the presence of the primary magnetic field generated by a logging tool's transmitter. In a exemplary embodiment of the present invention, a structure is provided having a new combination of electrical and mechanical design features which provide logging tool for internal calibration and checking of antenna performance and characteristics before during and after well logging operations. In one aspect of the invention a logging tool is provided comprising a verification winding for coupling a verification signal into the receiver coil.

Abstract: A method of determining the distribution of shales, sands and water in a reservoir including laminated shaly sands using vertical and horizontal conductivities derived from nuclear, NMR, and multi-component induction data such as from a Multicomponent Induction Logging Tool

Abstract: Measurements made by a cross-dipole acoustic logging tool in a borehole are processed to determine the principal directions of azimuthal anisotropy of a subsurface formation. Measurements indicative of azimuthal resistivity variations are also made with a multicomponent induction logging tool. These electrical measurements are processed using the principal direction determined from acoustic measurements to give an estimate of azimuthal resistivity variations. Based on modeling results, azimuthal resistivity variations are interpreted to estimate a fracture depth in the rock for known fluids therein.

Abstract: An improved induction tool for formation resistivity evaluations. The tool provides electromagnetic transmitters and sensors suitable for transmitting and receiving magnetic fields in radial directions that are orthogonal to the tool's longitudinal axis with minimal susceptibility to errors associated with parasitic eddy currents induced in the metal components surrounding the transmitter and receiver coils. Various transmitter receiver combinations are provided to select sensitivity to a desired reservoir formation properties, for example, different orientations xy, xz, yz, 20-40, 20-90, and combinations, such as, Symmetric—symmetric; Asymmetric—symmetric; and Asymmetric—asymmetric. Measurements made with a multi-component logging instrument when used in a substantially horizontal, vertical or deviated borehole in earth formations are diagnostic of the direction of resistive beds relative to the position of the borehole.

Abstract: The invention is a method of determining horizontal and vertical resistivity in an anisotropic formation using a combination of orientable triaxial and array antennae conveyed downhole. Measurements are taken at various azimuthal angles about a measuring device at a given depth. Values at each azimuthal orientation can be fit to a curve to yield information on the surrounding formation. Multiple measurements at a given depth and azimuthal orientation can be weighted to obtain an average value. Values from the curve fitting process are used in subsequent inversion processing and reduce the uncertainty of the inversion processing result. Utilization of a three dimensional geometry enables a unique resolution of the orientation of the principle axis of anisotropy, and consequently of horizontal and vertical resistivity, and dip.

Abstract: A transverse induction logging tool having a transmitter and receiver for downhole sampling of formation properties, the tool having a symmetrical shielded split-coil transmitter coil and a bucking coil interposed between the split transmitter coils to reduce coupling of the transmitter time varying magnetic field into the receiver. The tool provides symmetrical shielding of the coils and grounding at either the transmitter or receiver end only to reduce coupling of induced currents into the received signal. The tool provides an insulator between receiver electronics and the conductive receiver housing having contact with conductive wellbore fluid, to reduce parasitic current flowing in a loop formed by the upper housing, feed through pipe, lower housing and wellbore fluid adjacent the probe housing or mandrel. An internal verification loop is provided to track changes in transmitter current in the real and quadrature component of the received data signal.

Abstract: An improved induction tool for formation resistivity evaluations. The tool provides electromagnetic transmitters and sensors suitable for transmitting and receiving magnetic fields in radial directions that are orthogonal to the tool's longitudinal axis with minimal susceptibility to errors associated with parasitic eddy currents induced in the metal components surrounding the transmitter and receiver coils.

Abstract: The present invention is method of determining the distribution of shales, sands and water in a reservoir including laminated shaly sands using vertical and horizontal conductivities derived from nuclear, NMR, and multi-component induction data such as from a Transverse Induction Logging Tool (TILT). Making assumptions about the anisotropic properties of the laminated shale component and an assumption that the sand is isotropic, the TILT data are inverted. An estimate of the laminated shale volume from this inversion is compared with an estimate of laminated shale volume from nuclear logs using a Thomas-Stieber and Waxman-Smits model. A difference between the two estimates is an indication that the sands may be anisotropic. A check is made to see if a bulk water volume determined from the inversion is greater than a bulk irreducible water volume from NMR measurements. In one embodiment of the invention, NMR data are then used to obtain sand distribution in the reservoir.

Abstract: The invention is a method of determining horizontal and vertical resistivity in an anisotropic formation using a combination of orientable triaxial and array antennae conveyed downhole. Measurements are taken at various azimuthal angles about a measuring device at a given depth. Values at each azimuthal orientation can be fit to a curve to yield information on the surrounding formation. Multiple measurements at a given depth and azimuthal orientation can be weighted to obtain an average value. Values from the curve fitting process are used in subsequent inversion processing and reduce the uncertainty of the inversion processing result. Utilization of a three dimensional geometry enables a unique resolution of the orientation of the principle axis of anisotropy, and consequently of horizontal and vertical resistivity, and dip.

Abstract: A transverse induction logging tool having a transmitter and receiver for downhole sampling of formation properties, the tool having a symmetrical shielded split-coil transmitter coil and a bucking coil interposed between the split transmitter coils to reduce coupling of the transmitter time varying magnetic field into the receiver. The tool provides symmetrical shielding of the coils and grounding at either the transmitter or receiver end only to reduce coupling of induced currents into the received signal. The tool provides an insulator between receiver electronics and the conductive receiver housing having contact with conductive wellbore fluid, to reduce parasitic current flowing in a loop formed by the upper housing, feed through pipe, lower housing and wellbore fluid adjacent the probe housing or mandrel. An internal verification loop is provided to track changes in transmitter current in the real and quadrature component of the received data signal.

Abstract: The total porosity of said formation, a fractional volume of the shale, and a resistivity of the shale are determined in a laminated reservoir including sands that may have dispersed shales therein. A tensor petrophysical model determines the laminar shale volume and laminar sand conductivity from vertical and horizontal conductivities derived from multi-component induction log data. The volume of dispersed shale and the total and effective porosities of the laminar sand fraction are determined using a Thomas-Stieber-Juhasz approach. Removal of laminar shale conductivity and porosity effects reduces the laminated shaly sand problem to a single dispersed shaly sand model to which the Waxman-Smits equation can be applied.

Abstract: The distribution of shales, sands and water in a reservoir including laminated shaly sands using vertical and horizontal conductivities is derived from nuclear, NMR, and multi-component induction data. The multicomponent data are inverted and an estimate of the laminated shale volume from this inversion is compared with an estimate of laminated shale volume from nuclear logs. The bulk water volume determined from the inversion is compared with a bulk irreducible water volume from NMR measurements. NMR data are then used to obtain a sand distribution in the reservoir and this sand distribution is used in a second inversion of the multicomponent data. Alternatively, a bulk permeability measurement is used as a constraint in inverting the properties of the anisotropic sand component of the reservoir. From the resistivities of the sand laminae, empirical relations are used to predict anisotropic reservoir properties of the reservoir.

Abstract: Measurements made by a cross-dipole acoustic logging tool in a borehole are processed to determine the principal directions of azimuthal anisotropy of a subsurface formation. Measurements indicative of azimuthal resistivity variations are also made with a multicomponent induction logging tool. These electrical measurements are processed using the principal direction determined from acoustic measurements to give an estimate of azimuthal resistivity variations. Based on modeling results, azimuthal resistivity variations are interpreted to estimate a fracture depth in the rock for known fluids therein.

Abstract: Measurements made with a multicomponent logging instrument when used in a substantially horizontal borehole in earth formations are diagnostic of the direction of beds relative to the position of the borehole. When the logging instrument is conveyed on a drilling assembly, the drilling trajectory may be maintained to follow a predetermined trajectory or to maintain a desired distance from a boundary such as an oil-water contact.

Abstract: A logging while drilling and wire line system for analyzing the concentration of carbon dioxide or another substance, in a sample down hole in a bore hole. A chamber is filled with a sample that may be fluid, or condensate and gas. The interior chamber volume is selectably expandable for decompression of the sample. The sample may alternately be decompressed by allowing a sample at formation pressure to enter the chamber at a lower pressure, thereby decompressing the sample. A sensor measures the absorbance, transmittance or attenuated total reflectance of the infrared light. Mid and near infrared light is utilized to identify carbon dioxide, water and a plurality of hydrocarbons. A wiper cleans the transmitter and sensor between readings to reduce measurement error caused by fluid sample contamination.

Abstract: A method for characterizing a fluid sample withdrawn from an earth formation. The method includes performing nuclear magnetic resonant spin echo measurements on the fluid sample at a nuclear magnetic resonant frequency of carbon-13. Amplitudes of the spin echo measurements are summed. The summed measurements are spectrally analyzed. The fluid is characterized by determining whether aromatic hydrocarbons are present by measuring an amplitude of the spectrally analyzed spin echo measurements at about 130 part per million shift from the carbon-13 frequency. The fluid is also characterized by determining whether aliphatic hydrocarbons are present by measuring an amplitude of the spectrally analyzed spin echo measurements at about 30 parts per million frequency shift.